(O people! Take it easy on yourselves. Verily, you are not calling one who is deaf or absent, rather, the One you are calling is All-Hearer, Near (to His servants by His knowledge).) Ibn Jarir said that,

﴿تَضَرُّعًا﴾

(Tadarru`an), means obeying Him in humility and humbleness,

﴿وَخُفْيَةً﴾

(and Khufyah), with the humbleness in your hearts and certainty of His Oneness and Lordship not supplicating loudly to show off.